Carly Fiorina, the former Republican presidential candidate and chairwoman of Hewlett-Packard, said Monday that she believed it was “vital” that President Trump be impeached, but left open the possibility of voting for him in the fall of 2020.

In an interview that aired Monday on CNN’s “Boss Files with Poppy Harlow,” Ms. Fiorina called Mr. Trump’s conduct “destructive to our republic” and lamented that she no longer recognized the Republican Party.

“Loyalty to Trump is what I think it stands for,” she said.

Ms. Fiorina’s condemnation of her rival for the 2016 G.O.P. nomination comes just two days before a final vote in the House is expected on whether to impeach Mr. Trump. Mr. Trump is charged with having abused the power of the presidency by enlisting Ukraine to help damage political rivals and with obstructing Congress by blocking witnesses from testifying and refusing to provide documents.

In her interview with CNN, Ms. Fiorina said both that she believed Mr. Trump’s “conduct is impeachable” and that she thought he would in fact be impeached.

But she also said she did not know whether he should be removed from office following a trial in the Senate.

“I think it is vital that he be impeached,” Ms. Fiorina said of Mr. Trump. “Whether removed this close to an election, I don’t know.”

Ms. Fiorina said she had voted for Mr. Trump in 2016 and that she had been “very disappointed” with his tenure. Pressed on whether she would vote for him again, she said: “Honestly, it depends who the Democrats put up, and I won’t go any further than that.”

Mr. Trump repeatedly attacked Ms. Fiorina in the run-up to the 2016 Republican primary, disparaging her appearance and saying that her voice gave him a “massive headache.” Asked during a debate about Mr. Trump’s comments about her looks, she said: “I think women all over this country heard very clearly what Mr. Trump said.”

In the CNN interview, Ms. Fiorina said she did not know whether she would run for office in the future and would not say whether she would consider switching parties.